1. Field of the Invention
The present invention relates to a silicone composition for oral mucosa impression, which is used for undergoing oral mucosa impression taking with a good accuracy in the preparation or adjustment of dentures in the dentistry.
2. Description of the Related Art
In the dentistry, it is necessary to precisely reproduce the shape of an oral mucosa at the time of preparation or adjustment of a denture. If the shape of an oral mucosa is not precisely reproduced, the fittness between a denture base and an oral mucosa is lost, the denture likely becomes inferior in stability. As the result, when a patient masticates, not only the patient feels a pain on the oral mucosa, but also the mastication itself may become impossible with the denture coming out from the oral mucosa when the patient opens his or her mouth. For these reasons, there have been made various efforts for obtaining impression of the shape of an oral mucosa with a good accuracy using various impression materials. However, there are still various problems as described below, and the present state is that the impression taking with a good accuracy is not carried out.
In order to obtain the oral mucosa impression with a good accuracy, it is a necessary condition that in the impression taking, an impression material impresses precisely the shape of an oral mucosa without deforming the oral mucosa. For this, in bringing the impression material press-contacted with the oral mucosa, it is necessary to make a pressure to be applied to the mucosa press as low as possible. As the impression materials capable of obtaining the impression without applying an excessive pressure to the oral mucosa, there has since long been known a zinc oxide eugenol-based impression material. However, since this impression material has an irritation to the oral mucosa and gives an extreme pain to a patient at the time of impression taking, it is hardly used at the present time. For these reasons, dental impression materials developed mainly for the impression taking of crowns, bridges, and the like, such as an alginate, a polysulfide polymer, and a silicone, are usually used. However, since these impression materials do not flow unless a relatively high pressure is applied, an excessive pressure is applied to the oral mucosa at the time of impression taking, resulting in an incomplete impression with an inferior accuracy. In addition, the majority of patients who set a denture is a relatively aged person and is low to a vomiting reaction. Thus, in case of an impression material that readily flows spontaneously, there may be a danger that the impression material comes into the innermost part of a throat at the time of press contact.
Accordingly, in order to effect the oral mucosa impression taking with a good accuracy, an impression material is required to have such properties that although it flows by a very low pressure upon which the oral mucosa does not cause deformation, it does not come into the innermost part of a throat. Even materials having such properties can not be put into actual use if they have a large irritation to the mucosa.